NYU Albert says my major is undecided

I applied to NYU as an econ major though…

I’m already taking 2 Economics courses as of right now. If indeed I messed up somehow and didn’t declare my major, will those courses count when I do declare for econ?

Are you a freshman at NYU? When you apply to college as a specific major, you are not actually declaring that major, more like just expressing interest in it. You have to formally declare your major once at NYU through whatever procedure your department has outlined. It doesn’t matter whether you take classes before or after you declare, they will all count towards the major.